To meet a passenger's requirement for accessing the Internet in a rail transport vehicle, a wireless local area network technology may be used to dispose a vehicle-ground communications system. An in-vehicle access point (also referred to as AP) is disposed in a vehicle, and multiple trackside access points are disposed along a track. A wireless communication link is established between an in-vehicle access point and a trackside access point (for example, a mesh link or a wireless distribution system (WDS) link). The wireless communication link may support wireless communication between the in-vehicle access point and the trackside access point. A device of a passenger in the vehicle may access a network using the in-vehicle access point and further using the trackside access point. The in-vehicle access point and all the trackside access points use a same channel. When the vehicle is running, the in-vehicle access point is handed over between the multiple trackside access points. In a process of vehicle running, the in-vehicle access point listens to a signal of the trackside access point. If the in-vehicle access point finds that signal strength of a trackside access point meets a preset threshold, the in-vehicle access point may establish a wireless communication link to the trackside access point. In a process of continuous vehicle running, the in-vehicle access point finds that the signal strength of the trackside access point to which the wireless communication link was originally established becomes weaker, and a signal of another trackside access point becomes stronger. When signal strength of the other trackside access point meets the preset threshold, the in-vehicle access point may disconnect the original wireless communication link and establish a new wireless communication link to the other trackside access point.
A trackside access point may be interfered with by a radar signal or another signal, and interference may be avoided if the trackside access point is switched to another channel. However, a channel that is used by the trackside access point after channel switching and a channel that is used by another trackside access point and the in-vehicle access point are different. Therefore, establishment of a wireless communication link is affected. If the trackside access point does not switch an operating channel of the trackside access point, interference affects establishment of a wireless communication link. Further, some local regulations stipulate that when an access point uses some channels as operating channels, if detecting a radar signal, the access point needs to switch the operating channel of the access point. Therefore, interference from the radar signal or the other signal affects in-vehicle access point handover between the multiple trackside access points.